1. Field of the Invention
The present invention relates to a method for assigning a data service call of a wireless local loop (WLL) system and, more particularly, to a method for assigning packet resources of the WLL system supporting the data service call in consideration of the load amount of a packet processing apparatus.
2. Background of the Related Art
A data transmission method of a wireless communication system is divided into a circuit method and a packet method. In the circuit method, when a base station receives the call connection request of terminals and assigns the call to an empty channel, the assigned channel is exclusively used by the call until contact is cut off
In the packet method, the exclusive occupation of a channel is eliminated. When the base station receives the call connection request of terminals and assigns the call to an arbitrary packet processing processor, the assigned call monopolizes a channel only when there is data to be transmitted. When the data transmission is completed, the channel is changed to be idle and is allowed to be occupied by the call that approaches first.
The call transmitted from the terminal is speech (or character) data. The data is divided into a plurality of data items, each having a uniform length, so that they may be easily transmitted. Additionally, the data items are formed into a packet that is a data transmission unit. The packet includes the speech (character) information, transmission information, control information, and the address of a destination. These information elements are required for a wireless communication.
FIG. 1 shows the process of assigning the call in the circuit method. First, it is assumed that terminals 10, 20, and 30 are sequentially connected to a base station 80. When the terminal 10 tries to connect the call to the base station 80, a call assignment processor 40 detects an empty channel in a modem card 50 of the base station 80 and assigns the call to the empty channel. The calls of the terminal 10, which are sequentially tried to be connected to the remaining terminals 20 and 30, are assigned to the empty channels of the modem card 50 in the base station 80. At this time, the channels assigned to the respective terminals 10, 20, and 30 are monopolized until the connection of the calls is cut off by the corresponding terminal. The setting of the calls is maintained without the transmission of actual data.
FIG. 2 shows the process of sequentially assigning calls in a packet method. It is assumed that terminals 110, 120, and 130 are sequentially connected to a base station 180, that the load amount of a packet processing processor 160 is larger than the load amount of a packet processing processor 170, that a terminal is connected to the packet processing processor 160, and that two terminals are connected to the packet processing processor 170.
A call assignment processor 140 alternately and sequentially assigns the calls of the connected terminals 110, 120, and 130 to the respective packet processing processors 160 and 170 of packet board 150. The above assumed conditions, such as the current load amount of the packet processing processors 160 and 170 and the number of connected terminals, do not affect the performance of the present method.
When terminal 110 connects the call, which is assigned to the packet processing processor 160, the call of terminal 120, which is connected next in time, is assigned to the packet processing processor 170. The call of terminal 130, which is connected next in time, is assigned to the packet processing processor 160. When the number of packet processing processors is two, the calls are alternately assigned. When a plurality of packet processing processors operate, the calls are sequentially assigned.
“Sequentially” means that the call assignment processor 140 gives an equal call processing chance to the packet processing processor 160, according to the position of the packet processing processor as hardware or in the operation order of the packet processing processor as software.
FIG. 3 shows the process of assigning the calls according to the number of connected terminals in the packet method. It is assumed that terminals 210, 220, and 230 are sequentially connected to a base station 280, that the load amount of a packet processing processor 260 is larger than the load amount of the packet processing processor 270, two terminals are connected to the packet processing processor 260, and one terminal is connected to the packet processing processor 270.
In the method of assigning the calls according to the number of connected terminals, the number of terminals assigned to the packet processing processor 260 is compared with the number of terminals assigned to the packet processing processor 270, by call assignment processor 240, and a new call is assigned to the packet processor having a smaller number of terminals assigned to it. Because only the number of connected terminals is considered in the present method, it matters when a small number of calls are processed by the packet processing processor because the load amount of the packet processing process is large. In an embodiment according to the assumed conditions, a new call is assigned to the packet processing processor 260. Then, the number of terminals connected to the packet processing processor 260 is equal to the number of terminals connected to the packet processing processor 270. However, the load amount of the packet processing processor 260 is significantly different from the load amount of the packet processing processor 270.
When the number of terminals connected to the packet processing processor 260 is equal to the number of terminals connected to the packet processing processor 270, the calls of a newly connected terminal 220 are assigned by the method of sequentially assigning the calls. Therefore, the calls are assigned to the packet processing processor 260. The calls of the terminal 230 connected next in time are assigned to the packet processing processor 270, to which a smaller number of terminals are connected.
The methods of sequentially assigning the calls and of assigning the calls according to the number of connected terminals have the following problems.
In the case of the method of sequentially assigning the calls, because the two packet processing processors 160 and 170 sequentially receive the calls, the calls are appropriately assigned. However, if the load amount of the packet processing processor 160 is small because most of the calls assigned to the packet processing processor 160 are cut off and the load amount of the packet processing processor 170 increases because most of the calls assigned to the packet processing processor 170 still transmit and receive data, the method of sequentially assigning the calls imposes a heavier burden on the packet processing processor 170. This deteriorates the efficiency of the system.
In the case of the method of assigning the calls according to the number of connected terminals, the number of terminals connected to the packet processing processor 260 and the load amount of the packet processing processor 260 are not equal to the number of terminals connected to the packet processing processor 270 and the load amount of the packet processing processor 270. For example, let's assume that five terminals are connected to the packet processing processor 260 and three terminals are connected to the packet processing processor 270. At this time, even though most of the calls of the packet processing processor 260 are connected, assume little data is transmitted and received. Also, assume the load amount of the packet processing processor 270 is large because data is actively transmitted and received. Further assume a newly connected call is assigned to the packet processing processor 270, whose load amount is large. In this example, the packet processing load is not evenly distributed, causing packet processing processor 270 to support a disproportionate share of the load.
Because each packet processing processor must process a large number of calls in the packet data system, it is important to appropriately assign the calls so that the calls are concentrated to a packet processing processor.
In the circuit method, because each call occupies a channel even though data is not transmitted and received, the efficiency and flexibility in using a circuit is low. In the method of sequentially assigning the calls, the calls are assigned without considering the load amount of the packet processing processor and the number of connected terminals. In the method of assigning the calls according to the number of connected terminals, the calls are assigned to the packet processing processor without considering the load amount of the packet processing processor.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.